LISM STRUCTURE - FRAGMENTED SUPERBUBBLE SHELL

Small scale structure in local interstellar matter (LISM) is considere d. Overall morphology of the local cloud complex is inferred from Ca I I absorption lines and observations of H I in white dwarf stars. Cloud s with column densities ranging from 2-100 x 10(17) cm(-2) are found w ithin 20 pc of the Sun. Cold (50 K) dense (similar to 10(5) cm(-3)) sm all (5-10 au) clouds could be embedded and currently undetected in the upwind gas. The Sun appears to be embedded in a filament of gas with thickness less than or equal to 0.7 pc, and cross-wise column density less than or equal to 2 x 10(17) cm(-2). The local magnetic field dire ction is parallel to the filament, suggesting that the physical proces s causing the filamentation is MHD related. Enhanced abundances of ref ractory elements and LISM kinematics indicate outflowing gas from the Scorpius-Centaurus Association. The local flow vector and lambda Sco d ata are consistent with a 4,000,000 year old superbubble shell at simi lar to-22 km s(-1), which is a shock front passing through preshock ga s at similar to-12 km s(-1), and yielding cooled postshock gas at simi lar to-26 km s(-1)in the upwind direction. A preshock magnetic held st rength of 1.6 mu G, and postshock field strength of 5.2 mu G embedded in the superbubble shell, are consistent with the data.